In the past, there is known a server-client system in which a server manages content data and a client terminal downloads the corresponding content data from the server when necessary. Such a server-client system, for example, is constructed in Internet to which computers are interconnected using an Internet protocol technology, or intranet in which it is used in an intra-organization network within a company or the like.
For example, in software development fields, a server apparatus unifies a configuration management of software or an update management of a file under development, and each client terminal connected to the server downloads a source file or content from the server apparatus and performs various editing operations on downloaded content when appropriate and necessary. Therefore, the use of the server-client system has the advantage that content data within the server can be always maintained up to date and can be shared with each client terminal.
Also, in the past, a peer to peer (hereinafter, referred to as P2P) communication technology is known as a communication technology that mutually connects information processing devices such as computers and transmits data to the other side device. In the P2P type communication, since each personal computer becomes equivalent and no dedicated server is required, a communication network can be relatively easily organized.
The P2P type communication is suitable for construction of a small-scale LAN using, for example, four to six personal computers, and has the advantage that can reduce traffic because transmission is directly performed to the other side.
Furthermore, for example, Patent Literature 1 discloses a communication technology that reduces traffic passing through a server, efficiently transmits content data between processing devices, and realizes smooth and diverse communications between users of the respective information processing device in a server-client system. According to the technology disclosed in Patent Literature 1, the transition from the client-server type connection to the P2P type connection can prevent traffic to the server from being concentrated on one station and can achieve optimization of traffic in a whole system.